Expected Value (EV) Calculator
Calculate the expected profit or loss of a back bet from its odds, your estimated win probability and a USD stake. Compare expected ROI, break-even probability and both possible net results.
Enter the offered odds and your own estimate of the chance of winning. The probability is an assumption, not a forecast supplied by Macro Markets. Defaults are hypothetical.
Enter probability in percentage units: 55 or 55% means 55%; 0.55 means 0.55%. Endpoints 0 and 100 are allowed as assumptions. Stake must use whole cents, up to $1 billion. Use ungrouped numbers. Changing format clears the price.
Positive EV under your probability assumption. This is an estimated average across repeated comparable bets; a single bet can still lose the entire stake.
Models one back bet with a win or loss and stakes returned on wins. Fees, commission, taxes, promotions, pushes, voids and execution are excluded. Expected amounts can include fractions of a cent; displayed amounts are rounded estimates, not settlement instructions.
How to calculate betting expected value
- Choose American, decimal or fractional odds and enter the offered price.
- Enter your estimated win probability in percent and the USD stake. A probability estimate can be wrong; changing it changes the result.
- Compare expected profit and ROI with the break-even probability, then inspect the full win and loss scenarios. Include actual costs separately.
Hypothetical example: a $100 stake at +100 (2.0 decimal) with an assumed 55% chance gives $10 expected net profit and 10% expected ROI. A win nets $100; a loss nets −$100.
Compare a complete market with the no-vig calculator.Expected value calculator questions
What is the expected value formula for a bet?
Expected net equals win probability × net profit if it wins, minus loss probability × stake. At decimal odds D and probability p between 0 and 1, expected net is stake × (p × D − 1). Expected ROI is (p × D − 1) × 100%.
Where does the estimated probability come from?
You supply it from your own analysis or model. The odds imply a break-even probability, not a verified chance of winning. A complete-market no-vig calculation can provide a comparison, but it does not establish the true probability.
Why are probability edge and expected ROI different?
Probability edge is your estimated chance minus the break-even chance, measured in percentage points. Expected ROI is the expected profit divided by the stake, measured as a percentage. Odds affect the relationship between them.
Does positive expected value guarantee a profit?
No. The result depends on your probability estimate and entered price. A single bet can lose its entire stake, and actual costs can erase a modeled advantage. Contract fees, exchange lay bets, promotions, refunds and voids need a different model.
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